1. Field of the Disclosure
The disclosure relates to an electrofluidic display technique.
2. Description of Related Art
An electrofluidic display device is driven by varying an interface between polar fluid and non-polar fluid by applying an electric field.
FIGS. 1A-1B are schematic diagrams illustrating a driving mechanism of a conventional electrofluidic display device. Referring to FIG. 1A, polar fluid 104 and non-polar fluid 106 are filled between two transparent substrate 100a and 100b to form an interface 108. The polar fluid 104 is, for example, water containing pigment or colorant. The non-polar fluid 106 is, for example, transparent oil. Hydrophobic layers 102a and 102b are disposed on the two substrate 100a and 100b and contact the polar fluid 104 and the non-polar fluid 106 to form a convex interface. Moreover, an electrode layer 103 is disposed between the substrate 100a and the hydrophobic layer 102a. When an operating voltage is not applied, the polar fluid 104 is convergent due to surface tension of the hydrophobic layers.
Referring to FIG. 1B, when the polar fluid 104 is taken as a ground terminal, and a voltage 110 is applied to the electrode layer 103, the interface 108 is inclined under a function of the electric field, so that the polar fluid 104 is driven to move leftwards. An area covered by the polar fluid 104 presents a color of the added pigment or colorant.
The above driving mechanism can be used to design a display device. FIGS. 2A-2B are structural schematic diagrams illustrating of a conventional electrofluidic display device. Referring to FIG. 2A, an insulating material layer 122 is disposed on a transparent substrate 120a. The insulating material layer 122 has a groove 124. A hydrophobic layer 126 is disposed on the insulating material layer 122. An electrode layer 127 and a hydrophobic layer 128 are disposed on another substrate 120b. The electrode layer 127 can be a transparent conductive material, for example, indium tin oxide (ITO). Polar fluid 104 is disposed between the groove 124 and the hydrophobic layers 126 and 128, and non-polar fluid 106 is disposed between the two hydrophobic layers 126 and 128, and forms an interface balance with the polar fluid 104. The polar fluid 104 is, for example, water doped with pigment or colorant. The non-polar fluid 106 can be transparent fluid, for example, oil. When none voltage is applied, the polar fluid 104 is convergent in the groove 124 due to surface tension of the hydrophobic layers. Materials of the substrates are also transparent materials. The incident light may maintain its original color, for example, a white color to pass through the substrates 120a and 120b, the electrode layer 127 and the transparent non-polar fluid 106.
Referring to FIG. 2B, when the polar fluid 104 is regarded as the ground terminal, and a positive voltage is applied to the electrode layer 127, the polar fluid 104 is driven to move outwards from the groove 124 and distributed to other regions of the groove 124. Since the polar fluid 104 contains pigment and colorant, when the light passes through the polar fluid 104, the light present the color of the pigment or the colorant. When the voltage supply stop applying, the polar fluid 104 is pushed back to the groove 124 due to the function between the polar fluid 104 and the hydrophobic layers.
A conventional electrofluidic display panel is formed by a plurality of electrofluidic display devices arranged in an array. FIGS. 3A-3B are schematic diagrams illustrating an operation mechanism of the conventional electrofluidic display panel. Referring to FIG. 3A, each pixel has polar fluid 134 disposed in a groove, and non-polar fluid is filled to surround the polar fluid 134, and ducts 130 are disposed around the pixel, and the non-polar fluid is filled in the ducts 130 to separate each of the pixels during a driving process. When the operating voltage is not applied, the polar fluid 134 is maintained in the groove. Referring to FIG. 3B, when the operating voltage is applied, the polar fluid 134 is pulled out from the groove and distributed all over the pixel area. Since the polar fluid 134 is doped with pigment or colorant, a color display effect is achieved. The ducts 130 are used to avoid mutual interference of the polar fluids during the driving process.